In a photoresist process, which is one of semiconductor manufacturing processes, a resist is coated on the surface of a semiconductor wafer which is a substrate (hereinafter referred to as a wafer), the resist is then exposed to a predetermined light pattern, and then the resist is developed, so that a resist pattern is formed. The resist pattern is formed by using a coating and developing apparatus having various modules for performing various processes to the wafer.
To process the wafer accurately without defects, it is necessary to acquire data on each module before operating the coating and developing apparatus or during its inspection. For example, a liquid processing module, which applies a chemical liquid, such as the resist, to the wafer, is provided with a spin chuck that retains, by suction, the central part of the back surface of the wafer and rotates the wafer. Therefore, the chemical liquid supplied to the rotation center of the wafer spreads by centrifugal force. A pre-operational inspection is conducted to locate the rotation center of the spin chuck for the purpose of forming a highly uniform film of the chemical liquid. When the wafer is to be processed, the wafer is placed on the spin chuck in such a manner that the center of the wafer coincides with the rotation center of the spin chuck. In a heating module that thermally processes a wafer, the data on wafer heating temperature is acquired.
To acquire the above-described data, a sensor wafer on which various sensors are mounted is used. For example, the sensor wafer, which is wire-connected to a power supply section, is loaded into an inspection target module to acquire the data. However, if the sensor wafer is connected to the power supply section by a wire, it is troublesome for an operator to load the sensor wafer into the inspection target module. As a solution to this problem, it is proposed that the power supply section formed, for instance, by a lithium-ion secondary battery be mounted on the sensor wafer. Thus, the wafer can be loaded into the module by a substrate transport mechanism included in the coating and developing apparatus. This makes it possible to increase the efficiency of data acquisition. An inspection conducted with the sensor wafer having the power supply is described in JP2008-109027A.
However, the coating and developing apparatus includes many modules in order to increase its throughput. In order to perform measurements in all the modules for a predetermined period of time, a large-capacity battery, which is large-sized and heavy, is required. If such a battery is used, environmental conditions prevailing in a processing module into which the sensor wafer is loaded differ from the environmental conditions prevailing when a product wafer is loaded. This may decrease the accuracy of acquired data.